Powerful relics known as Precious have started to appear throughout the world. However, the various Negative Syndicates wish to take the Precious for themselves and utilize them for evil means. To make sure that the Precious do not fall into the hands of the Negative Syndicates, the Search Guard Successor Foundation has developed its own special operations team, the Boukengers, to do battle and collect some of the more dangerous Precious.

The Fast Adventurer, as Bouken Black he drives GoGo Formula, a racecar-like vehicle, and is only part of the Boukengers to pay his debt back to Akashi for saving his life. He has a personal vendetta against Yaiba of Darkness of Dark Shadow.

The Strong Adventurer, as Bouken Yellow she drives GoGo Dozer, a giant bulldozer, and is the most childish of the group. Her main reason to adventure was to discover more about her own past. It is later revealed that she is the last survivor of the Lemurian civilization.

The Deep Adventurer, as Bouken Pink she drives GoGo Marine, a giant submarine, and is the most serious member of the team when it comes to work. She often appears to be cold and emotionless, but cares for her teammates.

The Dazzling Adventurer, as Bouken Silver he drives GoGo Fire and serves as the spiritually strongest of the team because his father, the Ashu Watcher Karato wed with the Ashu Kei, making Eiji half-Ashu. He mostly battles against Gai (as either form) due to their bitter history. In Boukenger vs. Super Sentai, he embodies Hope.

They are led by Mister Voice, who serves as a liaison to the main S.G.S. headquarters, and they are assisted by Makino Morino, who is the technical specialist of S.G.S. and creator of the GoGo Vehicles, the mecha of the Boukengers.

One of Satoru's ex-partners who went on an expedition with him years ago. While searching for a Precious, Satoru accidentally set off a trap which created a ring of fire that neither she nor Masaki could escape and Satoru could not reach them. Satoru swore to get help and rescue them, but the trap triggered an explosion, killing Kyoko and Masaki before Satoru could even leave to find help. Portrayed by Miki Handa(繁田 美貴,Handa Miki?).

One of Satoru's ex-partners who went on an expedition with him years ago. While searching for a Precious, Satoru accidentally set off a trap which created a ring of fire that neither he nor Kyoko could escape and Satoru could not reach them. Satoru swore to get help and rescue them, but the trap triggered an explosion, killing Kyoko and Masaki before Satoru could even leave to find help. Later on, Rei tricked Satoru into believing that Gai was Masaki, still alive, so he could shoot him with the Fighter's Crossbow. Eventually Satoru saw through the illusion and went on. Portrayed by Yusuke Murakami(村上 裕亮,Murakami Yūsuke?).

She had been seeking the treasures from the Bamboo Cutter's story, crossing the Jyaryu Tribe while getting her fourth treasure, the Dragon's Neck Orb. She had all but one when she ran into Souta, who later returned to protect her against Jakuryuu Lindorm when she attempted to get the Potion of Immortality. It was shown in the end that Selene could have been Princess Kaguya herself. Portrayed by Nana Yanagisawa(柳沢 なな,Yanagisawa Nana?), who later portrayed Megumi Aso in Kamen Rider Kiva.

An elder from the Water Metropolis who didn't want to see any more of his people perish in the search for the Aqua Crystal. Turned Ragi's section of the Crystal Document into water, but Satoru remembered it from earlier and helped Ragi find the Crystal. Magi soon realized the error of his ways and give Ragi his blessing. Ragi and Magi were reunited as the ocean returned. Portrayed by Mike Maki(マイク 真木,Maiku Maki?), who previously portrayed Mondo Tatsumi in Kyuukyuu Sentai GoGoFive.

Magi's apprentice. Once a "Water human", he was intend to finish what his father started to restore the Water Metropolis. He sacrificed his humanity in order to survive without water by discarding the "Proof of Water" crystal on his tiara (which Ryuoon crushed) and was transformed into a Jaakuryuu by Ryuoon, who used him to find the Aqua Crystal. He could not regain his composure until Satoru took him under his protection. Eventually, Ragi was able to free the Aqua Cystal from a volcano and his transformation paid off. After Naga was terminated by Ultimate Daibouken, Ragi put the Aqua Crystal in its rightful place and returned to the City of Water, but, couldn't step into the sea waters until Satoru gave him the new crystal forged from the shattered remains of his father's Proof of Water as a thanks for the "greatest adventure". His Jaakuryuu form was based on Mirai Sentai Timeranger '​s TimeRobo Alpha. Portrayed by Takeru Shibaki(柴木 丈瑠,Shibaki Takeru?), who previously portrayed Kai Samezu/GaoBlue in Hyakujuu Sentai Gaoranger.

Eiji's father. While he was fighting Gai, Gai told a young Eiji that he was part Ashu and his mother was one of them. When Eiji's Ashu side came loose, Karato tried to calm Eiji down by embracing him, however Gai used this moment to slash him in the back. With his last breath he bestowed upon Eiji his shakujo so he could fight the Ashu. Portrayed by Hiroshi Watari(渡 洋史,Watari Hiroshi?), who previously portrayed Den Iga/Sharivan in Uchuu Keiji Sharivan and Yousuke Jou/Spielban in Jikuu Senshi Spielban.

First appearing in Task 19, she is the only female Ashu and is Eiji's mother, as a result of her and Karato's sharing of a forbidden love. After conversing with Natsuki, Souta, and Satoru by means of her spirit (trapped in a mirror), a tear-shaped jewel was left behind. Kei came to her son's aid during his fight with Ouga in Task 42, and helped him return to his world. She made a cameo in Task 48. Portrayed by Mami Higashiyama(東山 麻美,Higashiyama Mami?), who previously portrayed Miku Imamura/MegaPink in Denji Sentai Megaranger.

Souta's ex-partner from his times as a spy, kidnaping him in order to know the place where SGS kept the Imperial Pearl and steal it for the country. It's later revealed that he recruited the Questers to help him. Rei would forcefully extract from Souta's memory the location of the building so they could steal the Precious and Toba would receive the Imperial Pearl as payment. However, Yuji soon got a change of heart after hearing's Souta intend to make up for his crime. When the Questers finally locate the building and try to break into it with Quester Robo Turbo, Toba detonated a bomb he installed in the cockpit previously, giving SirenBuilder and Ultimate DaiBouken the chance to destroy the robot. He the called act a "parting gift" to Souta. Portrayed by Akira Kubodera(窪寺 昭,Kubodera Akira?), who previously portrayed Kanai/Giraffa Undead in Kamen Rider Blade and Kunzite in Pretty Guardian Sailor Moon.

Satoru's father and a UMA Hunter. He responds to Muse's call to obtain a strange prehistoric insect said not to exist. He and Satoru had been distanced because of their thoughts about what's an adventure. After confronting Hyde Gene, Kouichi acknowledges Satoru as an adventurer and a son to be proud of. Portrayed by Yasuaki Kurata(倉田 保昭,Kurata Yasuaki?).

Archeologist, well known for being the only known researcher of the most ancient civilization known, Lemuria, as well as one of the only two men who can read Lemurian, the other one being Ryuoon. Despises SGS for its "ambition", and treasure hunters because of the destruction of many ruins at their hands in search of Precious. Has been searching for the last known Precious of the Lemurian civilization: "The Egg of Lemuria" and "The Golden Sword". Acknowledges Satoru when the Sword lets him wield it as only the right-hearted can touch "The Golden Sword". Portrayed by Mansaku Fuwa(不破 万作,Fuwa Mansaku?).

A last-in-everything that was accepted in the Adventurer School after being mistaken for Satoru. In class, he was always target of Shirubegami's "Chalk Attack" as he was always screwing up. After Shirubegami's plans are revealed, the unapproved alumni were thrown to the sea along with the Accelulars of Natsuki and Souta and just when the others were about to be sacrificed, Shimada appears with the recovered Accellulars and gives the Boukengers the chance to destroy the Tsukumogami and rescue the alumni. Touched by the adventurer spirit that Shimada showed when recovering the Accellulars, the Boukengers learn that adventure is not something to learn in a school. Portrayed by Makoto Sakamoto(坂本 真,Sakamoto Makoto?).

A mysterious boy who was born from a giant peach Satoru and Eiji found in a river. The boy develops at an incredible speed growing in one day what a normal human would grow in 10 years. It's later revealed that he was sent by the mountain in which the "Mountain Crushing Kanabo" was hidden in order to recover it. He was a complete coward despite being his only goal to take back the Precious. Eventually could gather courage from Satoru and Eiji and stood against the Questers. Taro took away the Precious from Quester Robo Radial barehanded and returned to his mountain. He is based upon the Japanese legend of Momotarō.

A mysterious girl who claims to have been kissed and hugged by Souta and wants him to be with her, Souta doesn't remember even knowing her but she insists that he was very kind to her. It's later revealed that she is actually a cat which by means of a piece of "The Rainbow Cloth", transformed into a human in order to thank Souta for helping her fix her leg. When Shizuka used that same Precious to transform in Super Shizuka, Miyu, as a cat, sniffed the part of the cloth she had ripped off, consequently finding Super Shizuka's weak spot and allowing the Boukengers to defeat her. She was adopted by Souta after returning to her true form. Portrayed by Mizuho Hata(秦 みずほ,Hata Mizuho?).

A young girl Satoru met and who claims to be Santa Claus. She is attacked by Gaja in order to obtain the Golem, a Precious capable of destroying a large city. However, it turns out that Eve irresponsively gave the Golem in its doll form to a boy named Kiyoshi much to Satoru's annoyance while they were on a "date" to find Golem. but Gaja found it first, reviving Golem to attack the Boukengers with then enlarged itself. When the battle against the Golem seemed lost, Eve remembered the way to defeat it and revealed it to the Boukengers. She later thanks the Boukenger for helping her, promising another date with Satoru, and she flies away on her reindeer-drawn sleigh. Portrayed by Rina Akiyama(秋山 莉奈,Akiyama Rina?), who previously portrayed Mana Kazama in Kamen Rider Agito and later portrayed Naomi in Kamen Rider Den-O.

The embodiment of all of the past Red Sentai Warriors who gives Eiji the Super Sentai Address book to find older Sentai members to fight Chronos. After the Legend War where all Super Sentai lost their powers, Aka Red led the Red Pirates who were said to be the greatest rebel force ever to face the Zangyack. But when the Red Pirates were wiped out in a Zangyack attack due to Basco ta Jolokia's treachery, he saved the life of his crewmate Marvelous, making him promise to find the Greatest Treasure in the Universe before sacrificing himself to ensure Marvelous's escape. Voiced by Tōru Furuya(古谷 徹,Furuya Tōru?).

Veteran Sentai Warriors

Like the Dream Sentai in Gaoranger vs. Super Sentai. They appeared in Boukenger vs. Super Sentai. Along with Eiji, they embodied the "6 Sentai Spirits." These 5 warriors represented Passion, Courage, Friendship, Justice, and Love respectively.

A resident of Dino-Earth from Bakuryuu Sentai Abaranger, who gave the Abarangers the power to fight the Evolien meance. Asuka contacted Eiji from Dino Earth informing Eiji that AkaRed told of the situation. He embodies Passion.

Nickname, "Tetsu" (テツ,Tetsu?). A super elite member of the SPD who learned the true meaning of justice from his "Mentor" Ban of the Earth-branch Tokusou Sentai Dekaranger, who Tetsu had himself assigned to. He met Eiji when he was undercover and negotiating with the Polar Dragons Crime Syndicate. He was recruited by Eiji as he embodied Justice.

The second youngest son of the Ozu family and member of the Mahou Sentai Magiranger, he is the Yellow Magician, MagiYellow. His specialties are potions and the element of thunder. He was recruited by Eiji at a boxing match as he embodied Courage.

Tsubasa's brother in law, who taught him and his siblings the true potential of magic and fought by their side also he married Urara, Tsubasa's sister. He, along with his genie Smoky, helped the Boukengers out of Chronos' realm and embodied Love.

Not much is known about the Negative Syndicates (ネガティブシンジケート,Negatibu Shinjikēto?) other than they are individual organizations whose respective leaders, foot soldiers, and monsters try to steal the Precious and use them for evil deeds. This is the first series to have separate factions of villains since Seijuu Sentai Gingaman. Although there is some animosity between the member groups, they occasionally work together to serve their own ambitions.

Its sole survivor, High Priest Gaja (大神官ガジャ,Daishinkan Gaja?), intends to restore Goodomu its former glory by retrieving the Precious lost to them over the thousands of years they spent in slumber. Goodomu was the first and last Negative the Boukengers had to deal with. In the end, Gaja was defeated and re-entered hibernation to re-await his day of ruling the world.

Led by Creator King Ryuoon (創造王リュウオーン,Sōzōō Ryūōn?), once human, the Jyaryu seek to destroy mankind and make the Earth more suited to their reptilian bodies. However, most of the Jyaryu were wiped out near the series finale and Ryuoon lack the energy needed to make more, with only two seen a year and a half later in the epilogue. Ryuoon's whereabouts and condition are unknown.

A ninja clan under Gekkou of Illusion who uses both old and new items to create monsters called Tsukumogami (ツクモガミ?) to help them gather Precious for profit. After the betrayal and death of its member, Yaiba of Darkness, Dark Shadow dropped out of the Precious hunt and left the country during the finale until Gaja was defeated. Dark Shadow resumed its wicked ways in the epilogue.

Formerly of the demonic Ashu Tribe (アシュ族,Ashu Zoku?), Gai & Rei were revived by Gaja's Goodomu Engine quickly after being destroyed by the Boukengers and Eiji. They pursue Precious with intent on using them to achieve their goal of the complete genocide of the human race. They were eventually destroyed for good by the Boukengers.

Precious (プレシャス,Pureshasu?) are the dangerous treasures that the Boukengers and Negative are fighting over. For a relic to be considered a Precious, it must be physically or technologically superior to any current human (or SGS-related) technology. The hand-held Accellular henshin devices use their half-open Scan Mode to determine the "Hazard Level" of each relic; the higher the number, the more important or dangerous the Precious is. Each relic that ends up in the Boukengers' hands is placed into a box that materializes from a card-like device.

At the end of the segment for Hyakujuu Sentai Gaoranger (Task 28), the Boukengers wear the Gaorangers' jackets in their respective colors (Sakura wearing GaoWhite's) and perform their signature poses, complete with the Gao(牙吠?).

The 30 Sentai Encyclopedia (30戦隊大全集,Sanjū Sentai Daizenshu?) is a series of featurettes that air at the end of each episode (Task) of Boukenger that honors each of its predecessors in the Super Sentai franchise, starting with Task 4. They looked back at each of the 29 previous teams, referencing various items within the older shows, and later on, wearing the costumes and using other props from the series, such as the "civilian" clothing. After covering themselves, they start a new series of segments called the Special Files (スペシャルファイル,Supesharu Fairu?) that cover milestones from the "First Gattai Robo" to the "First Sixth Hero" and then from the "First Multi Gattai" to the "Extra Heroes", playing an insert song from the respective series. The show's final segment (Task 48) covered its successor Juken Sentai Gekiranger.

Episode 18 of Kamen Rider Kabuto showed a short preview for the Boukenger movie, and starting with Task 19, Boukenger showed its own previews. The movie is titled GoGo Sentai Boukenger The Movie: The Greatest Precious(轟轟戦隊ボウケンジャーTHE MOVIE 最強のプレシャス,GōGō Sentai Bōkenjā Za Mūvī Saikyō no Pureshasu?), which occurs between Tasks 28 and 29. It was released in theaters on August 5, 2006. A mysterious being called Muse (ミューズ,Myūzu?) awakens, announcing the Precious to whoever gets to her first, causing a 5-way confrontation between the Boukengers, Gaja, the Jyaryu, DarkShadow and the Questers. Even Satoru's father, Kouichi (虹一,Kōichi?) is involved. But as Satoru learns while dealing with his father ideals, the prize is more treacherous than the path to it.

As with all previous anniversary series, Boukenger features a team up special featuring five past Sentai members and a new hero, entitled GoGo Sentai Boukenger vs. Super Sentai(轟轟戦隊ボウケンジャー VS スーパー戦隊,GōGō Sentai Bōkenjā Basu Sūpā Sentai?).

The villain for this special, Time Demon Chronos (時の魔神クロノス,Toki no Majin Kuronosu?), abducts all of the Boukenger, save for Eiji, into an alternate dimension. A warrior known solely as Aka Red contacts Eiji on Earth and provide him a book that holds the names of all of the past warriors in it. He goes out and seeks the assistance of Tsubasa Ozu (MagiYellow of Mahou Sentai Magiranger) at a boxing match, Tekkan "Tetsu" Aira (DekaBreak of Tokusou Sentai Dekaranger) while he is undercover with the Polar Dragon Mafia, Asuka Ono (AbareBlack of Bakuryuu Sentai Abaranger) taking care of his daughter on Dino-Earth, and Nanami Nono (Hurricane Blue of Ninpuu Sentai Hurricaneger) at her concert. They then fight Chronos who has purchased Goodomu Engines from Gaja in order to bring back Furabiijo from Hurricaneger, revive Duchess Org Tsuetsue from Hyakujuu Sentai Gaoranger and Sorcery Priest Meemy of Magiranger. While the remaining Boukengers are in the other dimension, they meet up with Hikaru (MagiShine of Magiranger) and Smoky, his cat genie, and try to find a way to escape. When Chronos turns Meemy, Tsuetsue, and Furabiijo into a staff-like Precious with a Hazard Level of 666, Aka Red becomes a vessel for the six Sentai Spirits and allows for DaiVoyager to become Burning Legend DaiVoyager (バーニングレジェンドダイボイジャー,Bāningu Rejendo DaiBoijā?).